Home>> Gemstone Carat Weight Estimation Calculator

This calculator requires the use of Javascript enabled and proficient browsers. This script calculates the weight conversions between grams of weight and carats, points, kilograms and milligrams. Carats, shortened "ct." and spelled with a "c", is a measure of weight used for gemstones. The carat weight was uniform in the 20th century. The United States formally adopted the metric carat in 1913. One carat = .02 grams or 200 milligrams, equal to 1/5 of a gram. Stones are calculated to the nearest hundredth of a carat. A hundredth of a carat is also called a point. Hence a .10 carat stone can be called either 10 points, or 1/10 of a carat. Small stones like .05 and .10ct are most often referred as point designations. The spelling of karat with a "K" is a measure of the purity of a gold alloy, as opposite to stones. A one carat round diamond of average proportions is roughly 6.5mm in diameter. Be awake that this unique relationship of weight and size is different for each family of stones. For instance ruby and sapphire gems are both heavier than a diamond; technically, they have a higher specific gravity, so a 1 carat ruby or sapphire is smaller in size than a one carat diamond. Though, I never met a carat I didn't like!

Gemstone Carat Weight Estimation Calculator

Required Data
Unit
Number
Girdle Length (mm)
Girdle Width (mm)
Depth (mm)
Avg. Specific Gravity
   
Calculated Results
Carats Value

 

 

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